From the above output it is cleared that the routes which are coming from E-BGP peer are set with weight 0 and the routes which are redistributed in BGP from IGP are set with weight 32768. The above output depicts clearly that the route 3.1.1.0 belongs to R3-R1 wan link and 30.30.30.30 is the loopback address of R3 and coming with weight as 0. 4.1.1.0 is the wan pool of R2-R3 and 40.40.40.40 is the loopback of R2 are showing in BGP table with weight of 32768.

Now compare the outputs of table 3 and table 1. The difference is quite clear the routes which were coming with weight 0 now receiving the same routes with weight 32768. As I have already explained the local routes from IGP to BGP comes with weight 32768 and the E-BGP received routes come with weight 0.

Now the service provider link come up and by default the routing convergence should take place and all the routes should prefer from service provider cloud because E-BGP is having less administrative distance than OSPF. So let’s check what happens when the link comes up.

From table 5 and 6 it is cleared that the loopback route of R3 is coming via backdoor link instead of primary link which is up now. Table 6 output exhibit that the route is coming via IGP routing table and now redistributing to BGP.